I want to help clear up a few misconceptions. People realize that Piats don't actually have the range normal anti-tank weapons have right? So a squad has to run out in the open in a vain attempt to hit a light vehicle. Additionally the Luches comes in a faction that has an incredibly oppressive early game. That's the reason why it's timing needs to change. If it was on say, Wermacht then it's current timing would be fine. Since OKW can shut you off your fuel near the very start of the game, then seal the deal with the luches, that needs to be changed.
PIAT range has been increased from 30 to 35. However they will be pretty inaccurate at range 30-35 compared to other handheld AT. That, combined with RE nerfs and Tommy nerfs means that getting an AEC out as the brits every time vs Luchs will be a staple.
I can agree that USF light vehicles force a response, just like luches forces a response. The difference is USF banks on the fact they win early, cuz if they don't they aren't going to win at all. OKW still has an amazing late game to fall back on compared to USF. The Luches also just ruins any sort of diversity in build orders for USF and UKF. There can be an argument that Wermacht is forced to respond to threats with little in the ways of build orders but that's a separate problem then the Luches build time.
Hopefully DBP addresses late-game disparity. OKW still has infantry advantage with Volks and STGs very early on. As Volks performance starts to diminish, light vehicles. Eventually, in the lategame OKW will have to transition from a Volks-mostly army and pepper tanks and Obers as appropriate.
The main issue with USF is the rigidity of their tier structure. This would be trivially fixed by swapping Stuart with the M15.